There is no single answer to this question, but there are factors that, taken together, get us pretty close to an explanation. First, the kinds of industriesin a state form part of the answer. As men and women still tend to work in different industries and in different jobs, their opportunities and earnings vary by state. Second, the sector of the economy can also make a difference. The pay gap tends to be narrower in the public sector than in the private sector. In states with many public sector jobs, then, women and men are more likely to be paid similar wages. And third, the pay gap is narrower among workers who belong to unions. In states with large union presences, it’s more likely that women and men are paid more equally.

While major industries and types of jobs vary state to state, there is something everyone — lawmakers, employers, and individuals — can do to help close the gender pay gap.

Congress needs to pass the Paycheck Fairness Act. It’s a common-sense piece of legislation that would close loopholes in the 50-year-old Equal Pay Act and give employers and employees the tools they need to help close the gender wage gap.

Employers can make sure they are running a gender-fair workplace.While some business leaders have been vocal in their commitment to paying workers fairly, American women can’t wait for trickle-down change. We urge companies to conduct salary audits to proactively monitor and address gender-based pay differences. It’s just good business.

Women can learn strategies to better negotiate for fair pay and benefits.Improved negotiation skills can help close the pay gap and help women start off on better footing and build retirement savings.

It’s time that we value women’s work. If we truly valued all the women in our nation’s workforce and paid them fairly no matter where they live, our families would be more secure and our economy would have a brighter outlook. What are you waiting for?